With fast development of wireless communications technologies, users have higher requirements for data transmission rates. A Long Term Evolution (LTE) communications technology can provide a high-rate data network by using a high-speed low-delay flat network architecture, so as to satisfy the increasing rate transmission requirements of the users.
In a current LTE system, a user terminal may send an uplink reference signal to a base station within a transmission time interval (TTI). The base station may perform channel sounding, channel estimation, or frequency offset estimation for the user terminal according to the uplink reference signal sent by the user terminal, so as to schedule the user terminal according to a result of the channel sounding, or calibrate a frequency of uplink data of the user terminal according to a result of the frequency offset estimation and then receive, according to the calibrated frequency and a result of the channel estimation, the data sent by the user terminal. The TTI in the current LTE system is 1 ms. The TTI may be reduced to implement a shorter round-trip time and a shorter data transmission delay. If the TTI is reduced, to ensure that the base station normally receives the data sent by the user terminal, and/or that the base station normally schedules the user terminal, the user terminal needs to send sufficient uplink reference signals to the base station. That is, within the TTI, the user terminal needs to have sufficient resources for sending the uplink reference signals.
However, when the TTI is reduced, ensuring that the user terminal sends sufficient uplink reference signals decreases a capacity of data transmission by the user terminal within the TTI, reduces efficiency of data transmission, and decreases an uplink capacity of the system.